Which of the following plants produces both chasmogamous and cleistogamous flowers, and what is the primary advantage of
Plants like *Commelina*, *Viola* (Common pansy), and *Oxalis* produce both types. Cleistogamous flowers do not open at all. Their advantage is an assured seed set even in the absence of pollinators, as they are invariably autogamous.
Ref: Image of a Commelina or Viola plant showing open flowers above ground and closed flowers underground.